CICS Interview Questions with answers
The following is a small list of CICS interview questions with answers.
- · Define what is a CICS task?
Ans:-A CICS task is a single execution of a CICS transaction i.e. it exists from the time the operator keys in the transaction and presses the enter key until the application program returns control back toCICS.
Ans:- CWA is the acronym for common work area. It is a temporary storage area which any transaction can access. There is only one CWA for the entire system.
- · What are some of the common tables in CICS and their usage.
Ans:-
PCT (Program Control Table) – PCT contains a list of transaction identifiers paired with corresponding program.
PPT(Program Processing Table) – PPT contains a list of program names and the maps and whether a current version of program is in CICS or fresh copy needs to be loaded.
FCT( File Control Table) – FCT contains a list of files used by CICS, record length and their status (closed/open, enabled/disabled). Files are closed and opened by CICS and we don’t need file control section and opening and closing are not required in the program.
TCT(Terminal Control Table) – TCT contains a list of the terminals known to CICS.
RCT(Resource control Table)- RCT contains DB2 plan name and transaction identifier.
- · What is meant by reentrant program in CICS?
Ans:-In CICS a program is considered reentrant if more than one task can execute it without interfering with the execution of other tasks.
; ; ; ;
Ans:–COMMAREA or a communication area is a temporary storage area which is used to pass data between different programs loaded by a transaction and between different transactions at a given terminal.
- · What is meant by EIB (execute interface block)?
Ans:- EIB is the acronym used for Execute Interface Block. Each task has one EIB and it exists for the duration of the task. The EIB is same for all the programs that are part of the task. The fields from EIB can be easily accessed from the COBOL program in read mode.
The CICS translator generates the EIB block in the linkage area of the program. Following is the structure of an EIB.
01 DFHEIBLK.
02 EIBTIME PIC S9(7) COMP-3.
02 EIBDATE PIC S9(7) COMP-3.
02 EIBTRNID PIC X(4).
02 EIBTASKN PIC S9(7) COMP-3.
02 EIBTRMID PIC X(4).
02 EIBCPOSN PIC S9(4) COMP.
02 EIBCALEN PIC S9(4) COMP.
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Ans:- CEMT (master terminal transaction) is a system transaction id for inquiring the status or changing the status of resources
- · What are some of the common CICS service programs?
Ans:-
Terminal Control,
File Control,
Task Control,
Storage Control
The service programs stated above controls the usage and status for its resource (file, terminal, etc) within the CICS region.
- · What is an MDT (modified data tag) and what it is used for?
Ans:-Each field on the screen has the last bit for a special purpose and it is known as modified data tag. This bit (MDT) signifies if the field has been changed or not.
Ans:–Transid stands for transaction identifier. It is a four character code which is used to invoke a CICS task.